1. Field of the Invention
The present invention relates to a magnetic recording media, a method of manufacturing the recording media using imprint lithography, and a magnetic recording apparatus that uses the magnetic recording media.
2. Description of the Related Art
As demands for higher capacity of magnetic recording apparatuses, magnetic recording media are required to increase a recording density. Magnetic recording media with a high recording density have such a problem that, when data are recorded on a track with a magnetic head, data recorded on the adjacent tracks may be adversely affected with a high possibility. In order to solve the problem, there has been proposed a magnetic recording media, referred to as a discrete track media, in which tracks are formed of magnetic film that are physically discrete from each other in the track width direction. See, for example, Jpn. Pat. Appln. KOKAI Publication No. 62-256225.
Meanwhile, in the magnetic recording apparatus, the magnetic head positions itself with reading servo data from servo regions of the magnetic recording media. In the conventional magnetic recording media, the servo regions are magnetically recorded on the magnetic film using a servo track writer. On the other hand, it is preferable for the discrete track media that the magnetic film is processed to form servo marks in the servo regions as well as to form a pattern of the discrete tracks. Such a magnetic recording media, which is a type of a patterned media, should preferably be manufactured by using an imprint lithography method. Incidentally, when a size of the magnetic marks is reduced to about 500 nm or less, it is difficult to process the magnetic film into such a microstructure by photolithography. Electron-beam lithography enables to form the microstructure with a size of 500 nm or less. However, the electron beam lithography results in a low throughput because of slow drawing speed. In contrast, the imprint lithography method is advantageous, because the method permits to manufacture the patterned media at a high throughput.
A method of manufacturing a magnetic recording media, i.e., a patterned media, using imprint lithography will now be described.
First, an imprint stamper with a pattern of projections and recesses substantially reverse to that to be formed in the magnetic film on the magnetic recording media is prepared through, for example, the processes described below. An electron beam resist is applied to a master plate, and then a predetermined pattern is drawn to the resist by electron beam direct write. Development is performed to form a pattern of projections and recesses in the electron beam resist. The master plate on which the pattern of projections and recesses is formed in the electron beam resist is subjected to electroforming, and then the metal disk formed by electroforming is peeled off to prepare an imprint stamper.
Next, a magnetic recording media is prepared by using the imprint lithography method through, for example, the processes described below. That is, a magnetic film is formed on a substrate, and a resist is applied to the magnetic film. The imprint stamper is pressed against the resist to transfer the pattern of the projections and recesses on the surface thereof to the surface of the resist. After removing the imprint stamper, the magnetic film is processed using the resist to which the pattern has been transferred as a mask. Thus, a magnetic recording media, i.e., a patterned media, having a desired pattern of the magnetic film can be manufactured.
In the case where the imprint lithography method is used as described above, the imprint stamper prepared by using electron beam lithography can be used for the imprint steps over a number of times. Further, the imprint process brings about a higher throughput. Therefore, the cost for manufacturing the media can be reduced. Moreover, since the magnetic marks in the servo regions and the discrete tracks in the data regions can be formed at the same time, it is expected that accuracy in positions of the servo regions and the discrete tracks can be improved. Incidentally, in order to improve the recording density, it is advantageous that the imprint lithograph method should be applied to the manufacture of a perpendicular magnetic recording media.
However, when the magnetic recording media is manufactured by using the imprint lithography method, the thickness of the magnetic film may be made unevenly, depending on the pattern in the servo regions. As a result of this, it has become a problem that read and write of the magnetic data may be made unstable.